English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

With the $Karl~G.~Jansky$ Very Large Array (VLA) in C-configuration, weobserved a large portion of the first Galactic quadrant ($l=14.0-67.4^\circ $and $\lvert b \rvert \leq 1.25^\circ $) achieving an angular resolution of$\leq 40^{\prime\prime}$. At $L$ Band, the WIDAR correlator at the VLA was setto cover the 21~cm HI line, four OH transitions, a series of H$n\alpha$ radiorecombination lines (RRLs; $n=151$ to 186), and eight 128~MHz wide continuumspectral windows (SPWs) simultaneously. The HI emission shows clear filamentarysubstructures at negative velocities with low velocity crowding. The emissionat positive velocities is more smeared-out likely due to higher spatial andvelocity crowding of structures at the positive velocities. Comparing to thespiral arm model of the Milky Way, the atomic gas follows the Sagittarius andPerseus Arm well but with significant material in the inter-arm regions. Withthe C-configuration-only HI+continuum data, we produced a HI optical depth mapof the THOR areal coverage from 228 absorption spectra with thenearest-neighbor method. With this $\tau$ map, we corrected the HI emission foroptical depth and the derived column density is 38% higher than the columndensity with optically thin assumption. The total HI mass with optical depthcorrection in the survey region is 4.7$\times10^8~M_\odot$, 31% more than themass derived assuming the emission is optically thin. If we apply this 31%correction to the whole Milky Way, the total atomic gas mass would be9.4-10.5$\times 10^9~M_\odot$. Comparing the HI with existing CO data, we finda significant increase in the atomic-to-molecular gas ratio from the spiralarms to the inter-arm regions.

The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview